For a telecommunications network such as an ATM network, U.S. Pat. No. 5,224,099 issued to Corbalis et al on 29 Jun. 1993 discloses a method of queuing and servicing of cell traffic. The described techniques attempt to provide a fair servicing regime that satisfactorily handles different classes of traffic (voice, data etc) which have different quality-of-service priorities, in terms of delay and loss sensitivity.
Corbalis et al draw a distinction between bursty and non-bursty cell traffic. Bursty cell traffic is placed in one of a number of subqueues according to a hopcount associated with the respective cell. Each subqueue has a different servicing priority. Minimum bandwidths are respectively allocated to bursty and non-bursty traffic, and spare bandwidth is allocated to cell traffic according to a predefined priority scheme. The use of hopcount information (discussed in Corbalis et al), generally, has no bearing on the underlying congestion on the network. Accordingly, the use of hopcount information, as disclosed in Corbalis et al, does not provide a particularly advantageous way in which to address network congestion.
In packet-based computer networks, one widely used congestion avoidance algorithm is referred to as RED (Random Early Drop). According to this algorithm, the network drops packets when the average queue length at a network node, such as a router, is within a predetermined range.
The operation of RED and related algorithms is probabilistic and stateless, as packets are indiscriminately dropped at a certain rate, depending on the current average queue length. This approach is relatively unsophisticated, and accordingly does not make optimal use of network resources.
The above described existing techniques do not adequately or, in all cases, appropriately conserve network resources. Accordingly, a clear need exists for an improved manner of handling network traffic which at least attempts to address these and other limitations associated with existing techniques.